Spark g-ap



Aug, 26, 1924.

E. S. HUMPHREYS ET AL SPARK m? Filgd April 28 1922 INVENTOR lll Patented Aug". 25, 1924.

UNITED STATES EDVIIN S. HUMPHREYS AND FRANK MATTERN, OF CHICAGO, ILLINOIS.

SPARK GAP.

Application filed April 23, 1922. Serial no. 557,196.

To all-10. mm it may concern Be it known that we, EDWIN S. HUM- rnnnfs and FRANK MATTERN, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Spark Gaps, of which the following is a specification.

Our invention relates to improvements in spark gaps, and the principal objects thereof are t provide a spark gap which can be operated and read from a distance; to provide a spark gap with an automatically controlled indicator to prevent misreading; to provide a spark gap in which all mecha nism is protected and concealed; to provide a neat and rugged construction which shall be relatively simple in design and economical to manufacture, and in general to provide an improved and efiicient gap structure of the character referred to.

In the accompanying drawings which illustrate a sphere gap constructed in accordance with our invention,

Fig. 1 is a perspective view of the entire gap structure.

Fig. 2 is an enlarged sectional view of the indicator and bearing housing of the movable sphere, taken along the line 2-2 in Fig. 3. i

Fig. 3 is a sectional view along the line 33 in Fig. 4t and viewed in the direction of the arrow.

Fig. i is an enlarged fragmei'itary view of the indicator and bearing housing of the movable sphere.

These drawings illustrate one type of gap known as a sphere gap.

These drawings and description are made in this way because we prefer to embody our invention in a gap of this kind, but they can, iowever, be incorporated in any other type of gap without departing from the spirit of our invention.

Referring more particularly to Fig. 1, is the indicator and bearing housing of the movable sphere, 11, and 12 is the suport for the stationary sphere, 13. The iousing, 10, and the support, 12, are supported by posts, 1%, of insulating material, fastened in any manner, as for instance, by means of stud, 40, and threaded cross piece, 41, as shown in Fig. 3, which are in turn supported on a common base, 15, in any desired manner, as, for instance, by

means of collar, 16, and clamping rings, 17. The support, 12, has the socket, 18, on its one side, into which the ferrule, 19, of the resistance unit, 20, fits. A ball, 21, connected by means of the conductor, 22, to one pole of the source of high tension, 23, fits on the other ferrule, 2a, of this unit. The ball, 13, is attached in any desired fashion, as, for instance, by screw threads t one end of the rod, 25. The other end of this rod is adjustably mounted in the support, 12, as, for instance, by screw threads, 26, for a purpose which will be hereinafter explained. The housing, 10, has, as indicated in Fig. 2, the socket, 27, into which insulating sleeve, 28, is inserted. Conducting sleeve, 29,inturn is pushed into sleeve, 28, and forms a receptacle for ferrule, 30, of the resistance unit, 31. The other ferrule, 32, of this unit, terminates into a ball, 33, which is connected by means of conductor, 34, tothe other pole of the source of high tension, 23.

Referring now to Figs. 2, 3 and 4, ball 11 is mounted on shaft, 35, by means of screw threads, 36. Shaft is slidably mounted in bearings, 37 and 38, in the lower half, 39, of the housing, 10. A downwardly projecting pin, 42, is attached in any desired manner to shaft, 35, as, for instance, by means of the screw shown, and is provided with a hole, 43, through which the cord, td, is inserted and secured, as for instance by means of knot, 45.

An upwardly extending shaft, 46, secured by means of screw, 4C7, is mounted in lower half, 39, of the housing, 10. This shaft has a short upper turned down portion, d8, terminating in shoulder, 4.9, and longer turned down portion, 50, terminating in shoulder, 51. A cylindrical scale carrying member, 52, is rotatably mounted on the turned down portion, 50, resting on shoulder, 51. This member has a downwardly extending portion, 53. A spring, 54, is mounted inside this portion a-nd has its inner end fastened to shaft, 46, by mea'ns of screw, 55. Its other end passes through opening, 56, in the downwardly extending portion, 53, passes around the outside circumference of this member and is final y secured to the upwardly extending pin, 57, by means of loop, 58. The pin, 57, is secured by any desired means to shaft, 35, as by means of the screw indicated. The spring, 54:,

secured to the member, 53, near the opening, 56, by means of rivet, 59.

The cylindrical member, 52, carries scale, 60, on its outer circumference. An indicator lever, 61, ending at its one end in pointer, 62, whichcooperates with scale, 60, is pivotally mounted on the upper turned down section, 48, of shaft, 46, and rests against the shoulder, 49. Screw head, 63, serves to hold it in position. At two points, 64 and 65, the lever, 61, is formed downwardly into frictional engagement with the upper surface of member 52, for a purpose to be later described. The other end, 66, of the lever, 61, normally drops into the recess, 67, in the side of armature, 68. This armature is supported by means of spring, 69, and screw, 70 on the head, 10, and co-operates with a two pole electromagnet, 71, of ordinary construction fastened to head, 10, by means of screws, 72; the head, 10, being made of iron, closes the gap at one end and thus decreases the reluctance in a manner Well known to the art. One end, 73, of this winding of one of the magnets is connected to the sleeve, 29. The current then passes through the one winding to the wire, 74, which forms the other terminal of this winding and connects it to the Winding of the other magnet. -The current flows through wire, 74, through the second winding to wire, 75, which is grounded to the shell, 10. Any current going across the gap must therefore first pass through this winding and actuate the electromagnet in a manner well known to the art.

Spark are used for measurements of very high potentials, such as those used in X-ray work, and in the testing of insulators and insulating materials. Sphere spark gaps have better operating character istics than anyother type of gap and their use is gradually becoming more widespread for accurate work. Heretofore, however, this gap has practically been a laboratory instrument and little progress has been made to adapt it for routine work. All gaps were crudely designed and made, were inconvenient to operate and hard to read correctly. All of these difficulties have been overcome by this invention and the gap placed on a basis where it is an instrument of precision in ordinary work and at the same time is convenient to operate and economical to manufacture. A consideration of the method of use and operation of this. gap will illustrate the advantages of gaps made in accordance with our invention. The difference in potential to be measured is that across the terminals of the source of energy, 23. One pole is connected to conductor, 22, and the path of the current when the circuit is completed would be through this conductor, ball 21,

resistance unit, 20, head, 12, rod, 25, to sphere, 13. ,In. the same way the path of the current from the other pole would be through conductor, 34, ball, 33, resistance unit, 31, shell, 28, electromagnet, 71, head, 10, rod, 35, to sphere, 11. The circuit is not completed until the space between spheres 11 and 13 is reduced, so that the difference in potential between them is sufficient to break down the air between them. The distance at which this breakdown occurs is then a measure of this difference in potential. V

Traction on the cord, 44, causes the sphere, 11, to move toward the sphere, 13, as this traction is applied directly to the rod, 35, through the medium of the downwardly projecting lug, 43, to which the cord, 44, is attached. At the Sametime traction is exerted on the outer end of spring, 54, through the medium of the upwardly projecting pin, 57, also attached to rod, 35, to which pin this end of the spring, 54, is attached. This causes the scale carrying member, 52, and with it the scale, 60, to rotate counterclockwise, in Fig. 2, against the action of the inner convolutions of 7 spring, 54. The calibrations on the dial, 62, move past the opening, 76, in the head, 10. The indicator lever being in frictional e11- gagemen't with the .upper surface of the dial carrying member, 52, tends to rotate withthe latter, but is prevented because of the engagement of its end, 66, with one side of the recess, 67 in the armature, 68. As soon as the spacing has been reduced to a point where sparkover occurs, current passes through the windings of electromagnet, 71, and energizes it. The armature, 68, isthen attracted, releasing the end, 66, of the lever, 65, and allowing the latter to rotate with the dial carrying member, 52. The indicator, 62, is then temporarily fixed so that it indicates on the dial the exact point at which sparkover occurs, regardless of whether the spheres are stopped or moved closer together after the spark has passed. directly in kilovolts, or can be calibrated in distance between spheres as may be desired. The potential can therefore be read directly in terms of kilovolts or spacing, as the case may be. Upon release of the cord, 44, sphere 11 retreats from the vicinity of sphere, 13, under action of the inner convolutions of spring, 54. At the same time the dial, 60, turns back to its initial value and carries with it the lever, 62, until the side of the latter engages stop projecting downwardly from the upper part of head, 10. This stop is so located that when the current is caused to cease to pass across the gap and the electromagnet, 71, de-energized, the armature will resume the position shown in the drawings, and the opening, 67, in the This dial can either be calibrated latter will engage the end, 66, of the lever 61, holding it against rotation until sparkover again occurs.

lVhen for any reason it is necessary that the zero of the instrument be adjusted, this is done as followsi Without energizing the source or high potential, 28, traction is exerted on cord, 44; until the indicator, 62, indicates Zero. The sphere, 18, is then adjusted until it makes contactwith sphere 11. This is done by rotating the sphere, 13, causing it to screw or unscrew from the head, 12, as may be necessary.

From a consideration of the foregoing it is at once apparent that all personal error is eliminated, that the gap can be operated conveniently and can be read from a distance, and that the instrument is entirely practical for routine Work by other than trained laboratory aids.

\Vhile we have illustrated and described a particular embodiment or our invention, we do not Wish it to be understood as intending it to be limited thereto, as the same may be variously modified and altered Without departing from the spirit of our invention, it being our desire to claim our invention as broadly and completely as the prior state of the art will permit.

hat we claim as new and desire to secure by Letters Patent is:

1. In a device of the character described, a source of electrical energy whose difference. of potential is to be measured, a spark gap for measuring said difierence or potential, means for automatically causing an in dication of the spacing of the elements of said gap when the initial discharge passes between them upon movement of said elements toward one another and automatic means for resetting said indicator.

2. In a device of the character described, a source of electrical energy whose difference of potential is to be measured, a spark gap for measuring said difference of potential, electromagnetic means for automatically causing an indication of the spacing of the elements of said gap when the initial discharge passes between them upon movement of said elements toward one another.

3. In a device of the character described, a source of electrical energy whose difference of potential is to be measured, a spark gap for measuring said difference of potential, electrodes en said gap movable with respect to one another, a scale, means for inoving said scale in proportion to the movement of said electrodes, an indicator co-operating with said scale and normally fixed in position, and means for automatically causing said indicator to move with said scale upon the passing of the initial discharge upon movement of said electrodes.

4. In a device of the character described,

a source of electrical energy whose diflerence of potential is to be measured, a spark gap for measuring said difference of potential, electrodes on said gap movable with re spect to one another, a scale, means for moving said scale, in proportion to the movement of said electrodes, an indicator co-operating with said scale and normally fixed in position, and electromagnetic means for automatically causing said indicator to move with said scale upon the passing of the initial discharge upon movement of said electrodes.

5. In a device of the character described, a source of electrical energy whose difference of potential is to be measured, a spark gap for measuring said difference of potential, electrodes on said gap movable with respect to one another, a scale, means for moving said scale in proportion to the movement of said electrodes, an indicator cO-opei'ating with said scale and normally fixed in position, means for automatically causing said indicator to move with said scale upon the passing of the initial discharge upon movement of said electrodes, and means for returning said indicator to its initial position.

6. In a device of the character described, a source or electrical energy whose difference in potential is to be measured, a plurality of electrodes forming a spark gap for measuring said difference in. potential, means for moving said electrodes relative to one another, a scale connected with the said moving means to move with said electrodes, an indicator frictionally engaged with said scale, means for preventing movement or said indicator with said scale and means to allow said last named movement to take place upon the passage of the initial discharge between said electrodes.

7. In a device of the character described, a source of electrical energy whose difference in potential is to be measured, a plurality of electrodes forming a spark gap for measuring said difference in potential, means for moving said electrodes relative to one another, a scale connected with the said moving means to move with said electrodes, an indicator frictionally engaged with said scale, means for preventing movement or said indicator with said scale, and electromagnetic means to allow said last named movement to take place upon the passage of the initial discharge between said electrodes.

8. In a device of the character described, a source of electrical energy whose difference in potential is to be measured, a plurality of electrodes forming a spark gap for measuring said difference in potential, means for moving said electrodes relative to one another, a scale connected with the said moving means to move with said electrodes, indicator frictionally engaged with said scale, means for preventing movement of said indicator with said scale, means to allow said last named movement to take place upon the passage of the initial dis charge between said electrodes, and means for returningsaid indicator to its initial position.

7 9; In a device of the character described, a source of electrical energy whose difference in potential is to be measured, a plurality of electrodes forming a spark gap for measuring said difference in potential, means for moving said electrodes relative to one another, a scale connected with the said mov ing means to move with said electrodes, an indicator frictionally engaged with said scale, means for preventing movement of said indicator with said scale, electromagnetic'means to allow said last named movement to take place upon the passage of the initial discharge between said electrodes, and means for returning said indicator to its initial position.

10. In a device of the character described, a source of electrical energy whose difference in potential is to be measured, a plurality of electrodes forming a spark gap for measuring said difference in potential, means for moving said electrodes relative to one an other, a scale connected with said moving means, an indicator in frictional engagement with said scale and normally tending to move with the latter, an armature, means on said armature preventing the movement of said indicator with said scale, and an electromagnet arranged to withdraw said armature into an inoperative position to. allow said indicator to move with said scale upon passage of current across said gap.

11. In a spark gap, a stationary electrode, a movable electrode, means for moving aid last named electrode, a scale carrying member, means for communicating motion from said movable electrode to said last named member, an indicator, a frictional connection between said. scale carrying member and said indicator tending to cause said indicator to move with said scale carrying 'member, means for preventing said last named movement, means automatically operable upon passage of current across said gap to render said preventing means inoperable and allow said indicator to move with said scale.

upon passage of current across said gap to render vsaid preventing. means inoperable and allow said indicator to move with said scale, and a spring to return said movable electrode to its initial position upon diswith said shaft, an indicator co -operating with said scale, frlctlonal means connecting said indicator to said scale, means for holding said indicator against movement with said scale, meansifor rendering said last named means inoperable upon'passage of a discharge between said electrodes and an opening in said housing, whereby the rela' tire position of said scale and indicator can be ascertained. V

14;. In a spark gap, a pair of electrodes, a housing, bearings in said housing, an electrode carrying shaft slidably mounted in said bearings, a movable scale connected withsaid shaft, an indicator co-operating with said scale, frictional means connecting said indicator to said scale, means for holding said indicator against movement with said scale, electromagnetic means. for rendering said last named means inoperable upon passage of a discharge between .said electrodes and an opening in said housing whereby the relative position of said scale and indicator can be ascertained.

15. In a device ofthe character described, a source of electrical energy whose diflen ence in potential is to be measured, a spark 'gapvfor measuring said difference in potential and means for indicating the spacing of the elements of said gap at which the initial discharge passes after movement of said elements beyond said spacing.

16. In a device of the character described, a source'of electrical energy whose difference in potential is to be measured. a spark gap for measuring said difference in poten-' tial, a scale, and an indicator co-operating with said scale and means for fixing the positions of said scale and indicator relative to one another upon passage of a discharge across said gap.

17. ;In a device of the character described, a source of electrical energy whose difference in potential is to be measured, a spark gap for measuring said difference in potential, ascale, an indicator co-operating with saidscale, means for fixing the posit-ions of said scale and indicator relative to one an other upon passage of a discharge across said gap, and means for releasing the con nection between said scale'and indicator..-

EDWIN S. HUMPHREYS.

FRANK MATTERN. 

